implement-cqrs-handlers

implement-cqrs-handlers

Handlers live in src/Adapter/{Domain}/CommandHandler/ and QueryHandler/. See CQRS/CONTEXT.md for conventions (#[AsCommandHandler]/#[AsQueryHandler] attributes, no cross-handler calls, return types).

1. Add handler

Add{Domain}Handler.php implementing Add{Domain}HandlerInterface:

• Inject {Domain}Repository
• handle(Add{Domain}Command $command): {Domain}Id:
  • Construct the ObjectModel entity from command data
  • For multilingual fields, map $command->getLocalizedNames() to the lang array
  • Call $this->repository->create(...)
  • Return the new {Domain}Id
• Catch persistence exceptions, rethrow as domain exceptions

Reference: src/Adapter/Tax/CommandHandler/AddTaxHandler.php (simple), src/Adapter/Manufacturer/CommandHandler/AddManufacturerHandler.php (with image)

2. Edit handler (partial-update)

Edit{Domain}Handler.php implementing Edit{Domain}HandlerInterface:

• Load entity: $entity = $this->repository->get{Domain}($command->getId())
• For each field: if ($command->getName() !== null) { $entity->name = $command->getName(); }
• Apply only non-null fields — never overwrite with null
• Call $this->repository->update($entity)
• Sub-resource commands are dispatched independently, not composed here

Reference: src/Adapter/Tax/CommandHandler/EditTaxHandler.php (simple), src/Adapter/Carrier/CommandHandler/EditCarrierHandler.php (many fields)

3. Delete handler

Delete{Domain}Handler.php implementing Delete{Domain}HandlerInterface:

• Load entity to verify existence (throws {Domain}NotFoundException)
• Check business constraints: if entity is referenced by active orders/other entities, throw CannotDelete{Domain}Exception
• Call $this->repository->delete($command->getId())

4. Toggle status handler

Toggle{Domain}StatusHandler.php:

• Load entity by ID
• Flip: $entity->active = !$entity->active
• Call repository update
• Return void — the controller reads back state from the grid